轴向激励弹性连接双刚性球低频声辐射计算及分析

Calculation and analysis of low frequency acoustic radiation of two elastically-connected double rigid spheres under axial excitation

大潜深水下航行器一般采用多舱体结构,研究多舱体减振降噪方法意义重大。本文以球舱为例,利用球函数的平移加法理论,建立水下两个刚性球轴向振动产生的辐射声场的解析计算模型,比较100 Hz以下刚性模态的低频段内刚性球之间不同连接方式的辐射声场特性。计算结果表明,球体之间采用弹性连接能减小非受力刚性球的振速幅度,而且使两刚性球的振速相位之间存在相反的频段,各个刚性球的辐射声压相位相反,叠加时各部分声压会相互抵消,两球辐射强度相近时,声源级出现明显的谷点,激励力作用在等效密度大的球舱比作用在等效密度小的球舱降噪效果更好。该研究结论可以为水下航行器的多舱体低噪声设计提供参考。

It is of great significance to study the vibration and noise reduction method of the multi-cabin structures which are generally adopted by low noise large-deep underwater vehicles.An analytical model of the acoustic field radiated by the axial vibration of two elastically-connected rigid spheres was established in this paper using the translation addition theorem of spherical wave functions.The radiated acoustic field char⁃acteristics of different connection cases between the two rigid spheres below 100 Hz were compared,the two rigid spheres could be considered as a rigid body in this low frequency range.The calculation results show that the elastic connection between the spheres can reduce the vibration amplitude of the rigid spheres without external force.Moreover,there are opposite frequency bands between the vibration velocity phases of the two rigid spheres.The phases of sound pressure radiated by different spheres are opposite and the sound pressure of each part can cancel each other.When the radiation intensity magnitude of the two spheres is similar,the sound source level has an obvious low point.For two elastically-connected spheres,the force acting on one sphere with a large equivalent density can bring lower noise than that on the other sphere with a low equiva⁃lent density.The results can provide a reference for low noise design of multi-cabin underwater vehicles.